1. Field of the Invention
This invention relates to a golf ball mold capable of successively stamping an identification mark on golf balls in a simple and accurate manner.
2. Prior Art
In the past, golf balls bear an identification mark consisting of alphabet and numerical letters on their surface. The identification mark typically indicates the date and lot number of manufacture of golf balls.
In the prior art, such a mark is stamped on a golf ball using a stamping machine as shown in FIG. 6. The stamping machine designated at 20 includes a base 21, a circular table 22 resting on the base 21, an arm 23 pivotally connected to the base 21 for movement toward and away from the base, a holder 24 on the arm 23, and a stamp rod 25 received in the holder 24. The stamp rod 25 has a distal end face provided with a projection for stamping a symbol. In use, a golf ball G is secured on the table 22, and the arm 23 is pivotally moved downward to press the stamp rod 25 at its distal end against the surface of the golf ball G. Then the numerical or character symbol is stamped on the golf ball surface in the manner that the golf ball is locally compressed.
The prior art method, however, has several problems. It is difficult to accurately place all golf balls G to be stamped on the table 22 always at a predetermined position. In a usual practice, a ball is placed at an approximate position and stamped. Then the stamping position is not consistent throughout all balls. Since the pressing and stamping operation is manually carried out, the state of stamped symbols is not consistent. Some balls bear vaguely stamped symbols. Inversely, if the pressing operation is excessively strong, balls can be distorted thereby. The stamping operation requires the worker to carefully manipulate the stamping machine in a slow, accurate manner in order that the stamping position and the clearness of stamped letters be as constant as possible. The operation is laborious work requiring many moves and patience and thus needs skilled workers.